An arrangement largely of the type referred to in the introductory part which will allow this has previously been disclosed by FR 1 401 309 (see FIGS. 6 and 7). This arrangement is not designed to be capable of producing an automatic extension of the drive track in the final phase of tension wheel lowering. By virtue of its design construction the control arrangement for the tension wheel is bulky and can easily be exposed to damage from extraneous objects. The control cylinder for swivelling the tension wheel arm upwards and downwards in this arrangement is furthermore firmly affixed to the vehicle, in such a way that it is incapable of allowing rapid suspension movements of the tension wheel arm, when the tension wheel runs over a raised object on the ground, for example.
SE 0301046-9 (SE 525 073 C2) further discloses an arrangement for controlling a track tension wheel of a tracked vehicle, which has a telescopically length-adjustable tension wheel arm, which when lowered produces an automatic extension of the arm in order to simultaneously achieve a desired extension of the associated drive track running around the tension wheel. The tension wheel arm is controlled by two hydraulic cylinders pivotally mounted on the vehicle, which are situated outside the tension wheel arm. In order to permit suspension movements of the arm whilst driving on an uneven surface, one of the two cylinders may form a shock absorber in that the oil in the cylinder is allowed to flow through an associated restriction.
SE 0600274-5 (SE 529 600 C2) further discloses a track tension-adjusting arrangement of very compact construction, in which the hydraulic retracting and tensioning cylinders are protectively encapsulated in the actual tension wheel arm. This construction is relatively complicated, however, and costly to produce.